Carbon and silicon are mainly tetravalent while germanium, tin and lead also show divalency. Explain.

Why Carbon acts as insulator while Silicon and Germanium act as semiconductors?

This section contains assertion and reason type questions. Each question has 4 choice (1), (2),(3), and (4), out of which only one is correct. Assertion (A) Carbon is tetravalent and forms covalent bond. Reason ( R) Tetravalency can be explained in the terms of its electronic configuration and hybridisation of s- and p – orbitals.

Tin and lead form divalent Sn (II) and lead (II) and tetravalent i.e., Tin (IV) and lead. (IV) compounds. Tetravalent and dioxides of lead and Tin are amphoteric in nature. Lead tetra fluorite is ionic solid where as PbCl_(4) is covalent. Pbl_(4) does not exist. lead (II) halides are white whereas Pbl_(2) is yellow in colour. Q. SnCl_(2) is solid whereas SnCl_(4) is liquid, this is because?

Tin and lead form divalent Sn (II) and ead (II) and tetravalent i.e., Tin (IV) and lead. (IV) compounds. Tetravalent and dioxides of lead and Tin are amphoteric in nature. Lead tetra fluorite is ionic solid where as PbCl_(4) is covalent. Pbl_(4) does not exist. lead (II) halides are white whereas Pbl_(2) is yellow in colour. Q. Pbl_(4) does not exist due to